The movement of a combiner is usually locked in display position by an additional mechanism. The additional mechanism for the lock introduces extra costs, extra space, extra noise sources, and extra tolerances that must be considered in the project. The invention introduces a self locking mechanism that needs no extra components but only a feature integrated on the combiner elevation gear to lock the combiner in display position. A head up display with combiner elevation and a self locking mechanism with a flexible cover would be an improvement over the prior art.